Spinal Cord and Spinal Nerves Flashcards
Gray matter consist of:
mainly of neuronal cells bodies– divided into the dorsal horn, ventral horn, and lateral horn
White matter consist of:
mainly of neuronal fibers– divided into the dorsal funiculus, ventral funiculus, and lateral funiculus
Ventral Median Fissure
a distinct surface indentation present at all spinal cord levels and is related to the anterior spinal artery
Dorsal Median Fissure
a less distinct surface indentation present at all spinal cord levels
Dorsal Intermediate Septum
A surface indentation present only at and above T6 that distinguishes ascending fibers within the graciel fasciculus from ascending fibers within the cuneate fasciculus
conus medullaris
the end of the spinal cord, which occurs at vertebral level L1 in the adult and vertebral level L3 in the newborn
Cauda Equina
consists of the dorsal and ventral nerve roots of L2 through coccygeal 1 spinal nerves traveling in teh subarachoid space below the conus medullaris
Filum terminale
prolongatino of the pia mater from teh conus medullaris to the end of the dural sac at vertebral level S2 where it blends with the dura. Tha dura continues caudally as the filum of the dura mater, which attaches to the dorsum of the coccyx bone
The space in which contain fat and the internal vertebral venous plexus
Epidural Space
List 31 pairs of spinal nerves
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal
The four functional components of a spinal nerve
general somatic afferent (GSA), general somatic efferent (GSE_, general visceral afferent (GVA), ad general visceral efferent (GVE)
The muscle stretch reflex includes
the neuromuscular spindle, GSA dorsal root ganglion cell, GSE ventral horn gamma motor neuron, and the neuromuscular junction
Describe Lumbar puncture
Can be done to either withdraw CSF or inject an anesthetic; needle inserted either below or above the spinous process of the L4 vertebra; start from skin - superficial fascia - supraspinous ligament - interspinous ligament - ligamentum flavum - epidural space containing the internal vertebral venous plexus - dura mater - arachnoid - subarachnoid space containing CSF. The pia mater is not pierced.
Spinal anesthesia is produced by injecting anesthetic into which area? What happen?
the subarachnoid space; it produces anesthesia of the erineum, pelvic floor, and birth canal, along WITH the elimination if the sensation of uterine contractions and loss of motoe and sensory functions of the lower limbs
Sensory nerve fibers for pain from the uterus travel with the following nerves:
- Pelvic splanchnic nerves (parasympathetic) to S2 to S4 spinal levels from the cervix
- Hypogastric plexus and lumbar splanchnic nerves to L1 to L3 spinal levels from the fundus and body of the uterus and oviducts
To block the pain for vaginal childbirth Spinal anesthesia must be up to which spinal nerve? for cesarean section?
Spinal nerve T10; T4
Why do pregnant women require a smaller dose of anesthetic?
because the subarachnoid space is compressed because the internal vertebral venous plexus is engorged with blood from the pregnant uterus compressing the inferior vena cava
What are complications due to Spinal Anesthesia?
hypotension due to sympathetic blockade and vasolidation, respiratory paralysis involving the phrenic nerve due to high spinal blockade, and spinal headache do to CSF leakage
Where do you inject to produce Lumbar Epidural Anesthesia?
epidural space above or below the spinous process of the L4 vertebra OR (in case of participatory childbirth) inject into the epidural space of the sacral canal either through the sacral hiatus or the posterior sacral foramina
What happen in Lumbar Epidural Anesthesia?
The anesthetic will act upon S2-coccygeal 1 spinal nerves of the cauda equina producing anesthesia of the perineum, pelvic floor, and birth canal WITHOUT the eliminatino of sensation of the uterine contractions and loss of motor and sensory functions of the lower limbs
What are possible complications in Lumbar Epidural Anesthesia?
Respiratiry paralysis due to high spinal blockage; central nervous system (CNS) toxicity (slurred speech, tinnitus, convulsions, cardiac arrest) die to injection of the anesthetic into the internal vertebral venous plexus
Syringomyelia
a chronic progressive disease in which longitudinal cavities form in the cervical region of the spinal cord. This characteristically results in wasting of the muscles in the hands and a loss of sensation.
Chordomas
a malignant tumor arising from the embryonic remains of the notochord.
Paraplegia
transection anywhere between the cervical and lumbar enlargements of the spinal cord (paralysis of lower limbs)
Quadriplegia
transection above C3. These individuas may die quickly due to respiratory failure if the phrenic nerve is compromised (paralysis of all four limbs)
List any complications of SCI (Spinal cord injury); What medicine can you use to help?
hypotension in the acute setting, ileus, renal stones, pyelonephritis, renal failure, and deep venous thrombosis; Methylprednisolone (within 8 hours injury)
Astrocytomas
a tumor composed of astrocytes; the most common type of primary brain tumor and also found throughout the central nervous system
Meningiomas
a benign, slow-growing tumor of the meninges, usually next to the dura mater, which may invade the skull or cause hyperostosis, and often causes increased intracranial pressure
Schwannomas
a neoplasm originating from Schwann cells (of the myelin sheath) of neurons; schwannomas include neurofibromas and neurilemomas.
